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Ublas :

From: Gunter Winkler (guwi17_at_[hidden])
Date: 2007-03-09 14:38:59

Am Freitag, 9. März 2007 17:19 schrieb Nico Galoppo:
> Is it really a reference? I thought it depended on the
> implementation, e.g. row-major vs. column-major matrix classes etc.

It acts as a reference. (It actually consists of a reference to the
matrix and an index).

> I agree with Karl though that it probably doesn't return a copy. It
> is my understanding that, with expression templates, the actual data
> access is deferred to the point where it is actually used. (Unless
> you explicitly make temporary copies).

Yes, this is the key idea of uBLAS' expression templates.